Background: The molecular details of the effects of DOPAL on ␣-synuclein misfolding and oligomerization are unknown. Results: DOPAL forms Schiff-base and Michael-addition adducts with ␣-synuclein Lys residues. Conclusion: DOPAL modification inhibits aS fibrillization and reduces binding of ␣-synuclein to synaptic-like vesicles. Significance: DOPAL modification may interfere with the normal functions of ␣-synuclein and favor the buildup of potentially toxic oligomers.

No abstract

In this study, we performed a proteomic analysis of plastids isolated from the endosperm of developing Jatropha curcas seeds that were in the initial stage of deposition of protein and lipid reserves. Proteins extracted from the plastids were digested with trypsin, and the peptides were applied to an EASY-nano LC system coupled inline to an ESI-LTQ-Orbitrap Velos mass spectrometer, and this led to the identification of 1103 proteins representing 804 protein groups, of which 923 proteins were considered as true identifications, and this considerably expands the repertoire of J. curcas proteins identified so far. Of the identified proteins, only five are encoded in the plastid genome, and none of them are involved in photosynthesis, evidentiating the nonphotosynthetic nature of the isolated plastids. Homologues for 824 out of 923 identified proteins were present in PPDB, SUBA, or PlProt databases while homologues for 13 proteins were not found in any of the three plastid proteins databases but were marked as plastidial by at least one of the three prediction programs used. Functional classification showed that proteins belonging to amino acids metabolism comprise the main functional class, followed by carbohydrate, energy, and lipid metabolisms. The small and large subunits of Rubisco were identified, and their presence in the plastids is considered to be an adaptive feature counterbalancing for the loss of one-third of the carbon as CO2 as a result of the conversion of carbohydrate to oil through glycolysis. While several enzymes involved in the biosynthesis of several precursors of diterpenoids were identified, we were unable to identify any terpene synthase/cyclase, which suggests that the plastids isolated from the endosperm of developing seeds do not synthesize phorbol esters. In conclusion, our study provides insights into the major biosynthetic pathways and certain unique features of the plastids from the endosperm of developing seeds at the whole proteome level.

No abstract

A strategy for treating cancer is to surgically remove the tumor together with a portion of apparently healthy tissue surrounding it, the so-called "resection margin", to minimize recurrence. Here, we investigate whether the proteomic profiles from biopsies of gastric cancer resection margins are indeed more similar to those from healthy tissue than from cancer biopsies. To this end, we analyzed biopsies using an offline MudPIT shotgun proteomic approach and performed label-free quantitation through a distributed normalized spectral abundance factor approach adapted for extracted ion chromatograms (XICs). A multidimensional scaling analysis revealed that each of those tissue-types is very distinct from each other. The resection margin presented several proteins previously correlated with cancer, but also other overexpressed proteins that may be related to tumor nourishment and metastasis, such as collagen alpha-1, ceruloplasmin, calpastatin, and E-cadherin. We argue that the resection margin plays a key role in Paget's "soil to seed" hypothesis, that is, that cancer cells require a special microenvironment to nourish and that understanding it could ultimately lead to more effective treatments.